Pressure relief valve for structure

ABSTRACT

A pressure relief valve for structure. A valve with a spoiler around its edge sits in a valve seat around a structure valve aperture, and is spring-loaded into a closed position. Storm wind entering the structure through a breached window, door, or other structure opening escapes through the valve, which opens when exposed to a pressure differential of approximately 1.5 psi. Lift created by storm wind impinging on the spoiler tends to urge the upwind side of the valve closed. The valve may incorporate a skylight. In the preferred embodiment, the shape of the valve was a spherical or spheroid section, and the spring-loading was provided by a plurality of spring assemblies disposed around the edge(s) of the valve.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to structures, and in particular to a pressure relief valve for structure.

2. Background of the Invention

A common destruction sequence for building structures during windstorms such as hurricanes and tornadoes involves the following steps: 1. An opening such as a window or door is blown in on the upwind side of the structure; 2. The pressure of the air inside the building rises due to strong wind entering the breached opening; and 3. The internal air pressure literally blows the roof off of the structure. In the case of a tornado, the building actually explodes due to the sudden pressure differential of air trapped inside vs. the greatly reduced air pressure outdoors as the tornado approaches closely.

In this scenario, severe building damage results, clearly from the loss of the roof itself, but also from the ensuing water damage caused by the frequently torrential rain which falls directly into the structure. The problem of wind damage to buildings will probably get worse in the future, due to the natural hurricane cycle, which is currently on the ascendancy, and also due to increased storm strength due to global warning.

Thus, it would be desirable to provide a means of relieving the internal pressure of structures during wind storms, so as to avoid blowing their roofs off.

Existing Designs

A number of approaches have been hazarded to address this problem. U.S. Pat. No. 6,484,459 was granted Platts for a counter-pressure method which involved installing a number of window and door valves to relieve interior pressure. While this approach apparently relieved inside pressure, it was cumbersome to install the requisite valves at various locations in the structure to be protected, was very slow for tornados, and lacked the very high quality flow required for timely pressure equalization.

U.S. Pat. No. 7,001,266 was granted Jones et al. for a rooftop vent, which was designed to reduce inside pressure. This vent was permanently open, and appeared to suffer from the disadvantage that rain could enter the structure, given sufficient wind.

U.S. Pat. Nos. 6,206,774, 6,558,251 and 6,293,862 issued to Dexter et al., Sells and Jafine et al. respectively, for roof vents. While these designs appeared capable of relieving pressure internal to a building, no means for doing so on the down-wind side was taught, because these valves could not change their angle relative to the roof upon which they were mounted.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a pressure relief valve for structure which is capable of instantly relieving windstorm-induced pressure interior to a structure. Design features allowing this object to be accomplished include a plurality of springs urging a valve into a valve seat, the springs being sized to permit the valve to open when a pre-determined pressure differential between air pressure exterior to the structure and air pressure interior to the structure has been reached, e.g. 1.5 pounds per square inch (“psi”). Benefits associated with the accomplishment of this object include reduction of the possibility of the roof being blown off the structure due to windstorm-induced pressure interior to a structure, and the attendant cost savings in repair.

It is another object of the present invention to provide a pressure relief valve for structure which is normally closed. Design features allowing this object to be accomplished include a plurality of springs urging a valve into a valve seat. Advantages associated with the accomplishment of this object include reduced entry of precipitation, and reduced attendant water damage to the structure.

It is still another object of this invention to provide a pressure relief valve for structure whose up-wind side will tend to remain closed while its down-wind side opens to relieve pressure interior to a structure. Design features enabling the accomplishment of this object include a valve having spoiler along its edge(s), which spoils the smooth airflow like ice on an airplane wing destroys lift, thus causing the storm wind itself to urge the valve upwind side to remain closed.

Advantages associated with the realization of this object include less entry of wind-driven precipitation into the structure (because the valve opens for only seconds in a tornado), and the associated reduced water damage and lower cost of repair.

It is another object of the present invention to provide a pressure relief valve for structure which may be installed in a single location. Design features allowing this object to be accomplished include a valve seat disposed around a building valve aperture, and a plurality of springs urging a valve into the valve seat. Benefits associated with the accomplishment of this object include instantaneous speed, simpler and lest costly installation, better reliability, and reduced maintenance cost.

It is still another object of this invention to provide a pressure relief valve for structure which may be secured in place using a single cable. Design features enabling the accomplishment of this object include a single cable entering and exiting a valve seat and valve through a plurality of springs. Advantages associated with the realization of this object include simpler construction, along with the associated reduction in cost.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with the other objects, features, aspects and advantages thereof will be more clearly understood from the following in conjunction with the accompanying drawings.

Five sheets of drawings are provided. Sheet one contains FIGS. 1 and 2. Sheet two contains FIGS. 3 and 4. Sheet three contains FIGS. 5 and 6. Sheet four contains FIGS. 7 and 8. Sheet five contains FIGS. 9 and 10.

FIG. 1 is a side isometric view of a pressure relief valve mounted at the top of a structure.

FIG. 2 is a side isometric view of a pressure relief valve which has opened to relieve pressure internal to the structure to which it is mounted.

FIG. 3 is a side cross-sectional view of a closed pressure relief valve mounted to a structure.

FIG. 4 is a side cross-sectional view of a pressure relief valve which has opened to relieve pressure internal to the structure to which it is mounted.

FIG. 5 is a side cross-sectional view of the spring-loaded mounting of a pressure relief valve in the closed position.

FIG. 6 is a side cross-sectional view of the spring-loaded mounting of a pressure relief valve in another open position, such as may occur in the presence of an approaching tornado due to pressure differential.

FIG. 7 is a side cross-sectional view of the spring-loaded mounting of a pressure relief valve in an open position, such as may occur when wind increases and the pressure differential has mostly subsided.

FIG. 8 is a side cross-sectional view of an alternate embodiment spring-loaded mounting of a pressure relief valve in the closed position.

FIG. 9 is a detail side cross-sectional view of the spring-loaded mounting of a pressure relief valve in the closed position.

FIG. 10 is a detail side cross-sectional view of the spring-loaded mounting of a pressure relief valve in an open position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIG. 1, we observe a side isometric view of a pressure relief valve 2 mounted at the top of structure 4. Structure 4 comprises door 6 and windows 8. FIG. 2 is a side isometric view of valve 2 which has opened to relieve air pressure internal to structure 4. As may be observed in FIG. 2, valve 2 seats in valve seat 3, which is disposed around structure valve aperture 7. Spoiler 15 is disposed around the edge of valve 2. Unless opened by internal pressure within structure 4, valve 2 is normally spring-loaded, and/or urged by gravity, into the closed position depicted in FIG. 1. In the preferred embodiment, an internal structure pressure of as little as 1.5 pounds per square inch (psi) sufficed to open valve 2.

Referring now to FIG. 2, storm wind 14 has breached a window 8 such as may occur during a hurricane, and is now blowing into structure 4 via broken window 10. Valve 2 has opened against its spring-loaded mounting as indicated by arrow 16, and is permitting escaping air 18 to exit structure 4 through structure valve aperture 7, thus avoiding over-pressurization of structure 4, and its possible catastrophic failure. When pressure internal to structure 4 caused by storm wind 14 has subsided, valve 2 returns to its closed position depicted in FIG. 1 under the urging of its spring-loaded mounting and/or gravity. Although the figures depict the breach in structure 4 occurring through broken window 10, valve 2 will function regardless of where the breach occurs, e.g. in door 6.

FIG. 2 also depicts an alternate embodiment valve 2 which incorporates skylight 12. Skylight 12 serves to permit ambient illumination to enter structure 4, which is often important given the heavy darkness and frequent electrical power outages (shutting off the lights) which accompany hurricanes and tornadoes.

FIG. 3 is a side cross-sectional view of a closed pressure relief valve 2 mounted to structure 4. FIG. 4 is a side cross-sectional view of a pressure relief valve 2 which has opened to relieve pressure internal to structure 4. Storm wind 14 not only enters structure 4 via broken window 10, but storm wind 14 also impinges on the upwind side of valve 2, as may be observed in FIGS. 3 and 4. Pressure exerted by storm wind 14 on the upwind edge of valve 2 tends to keep the upwind edge of valve 2 seated, so that only the downwind edge of valve 2 opens due to pressure internal to structure 4, as depicted by arrow 20 in FIG. 4. This situation is also depicted in FIG. 7, a side cross-sectional view of the spring-loaded mounting of valve 2 in an open position. The act of valve 2 opening as indicated by arrow 20 in FIG. 4 permits escaping air 18 to exit structure 4, thus avoiding its over pressurization.

Spoiler 15 is disposed around the edge of valve 2, and serves to spoil the smooth airflow, like ice on an airplane wing destroys lift, thus causing the storm wind itself to urge the upwind side of valve 2 to remain closed. In FIGS. 3 and 7 we observe smooth storm wind 14 impinging on spoiler 15, which disturbs the smooth air flow and turns it into turbulent air flow 17. Turbulent air flow 17 exerts much less lift on the upwind edge of valve 2 than smooth air flow, thus helping keep the upwind edge of valve 2 down. Expressed differently, spoiler 15 disposed along the upwind edge of valve 2 helps keep the upwind side of valve 2 closed.

Although in the preferred embodiment the cross-sectional shape of spoiler 15 was round, as depicted in FIGS. 1 and 3-8, it is intended to fall within the scope of this embodiment that spoiler 15 be any appropriately shaped spoiler disposed around the edge of valve 2.

Even if the upwind side of valve 2 were to rise, thereby admitting storm wind 14, the downwind side of valve 2 would open (or remain open), thereby allowing storm wind 14 to escape structure 4 as escaping air 18. In this case, valve 2 would elevate above valve seat 3 as indicated by arrow 28 in FIG. 6, and spindles 26 would prevent valve 2 from blowing off structure 4.

FIG. 5 is a side cross-sectional view of the spring-loaded mounting of pressure relief valve 2 in the closed position. FIG. 6 is a side cross-sectional view of the spring-loaded mounting of pressure relief valve 2 in an open position. FIGS. 9 and 10 are detail side cross-sectional views of the spring mounting of valve 2 on structure 4. Referring to these figures, valve 2 is spring-bloodedly mounted to structure 4 by means of a plurality of spring assemblies 9 disposed around structure valve aperture 7. Valve 2 seats in valve seat 3, which is disposed around structure valve aperture 7.

As may be more clearly observed in FIGS. 9 and 10, spring assembly 9 comprises a spindle 26 slidably inserted through a valve spindle aperture 38, a corresponding structure spindle aperture 36, and a spring 22 disposed inside structure 4. Spindle stop 40 is attached to an upper end of spindle 26. Spindle stop 40 is sized to be larger than valve spindle aperture 38, thus preventing the end of spindle 26 to which spindle stop 40 is attached from sliding through valve spindle aperture 38.

Spring 22 is sandwiched between spring stop 24 at a lower end of spindle 26, and structure 4. Spring 22 may be pre-loaded so as to urge valve 2 into contact with valve seat 3, as indicated by arrow 42 in FIG. 9. In the preferred embodiment, springs 22 were installed with sufficient compression so as to require a pressure differential of approximately 1.5±1 psi to open valve 2. In an alternative embodiment, the weight of valve 2 keeps valve 2 closed, and springs 22 may be installed without any compressive pre-load, but rather serve to resist the opening of valve 2, and to return it to a closed position after internal pressure in structure 4 subsides.

An alternate embodiment could place spring 22 between spindle stop 40 and valve 2, in which case spring stop 24 would be sized to be larger than structure spindle aperture 36, thus preventing the end of spindle 26 to which spring stop 24 is attached from sliding through structure spindle aperture 36. Spindle 26 could be any appropriate elongate member, including but not limited to cable, chain, a metal or synthetic rod, a bolt, etc.

FIG. 8 is a side cross-sectional view of an alternate embodiment spring-loaded mounting of a pressure relief valve 2 in the closed position. In this embodiment, spindle 26 is one long elongate member, such as cable 32, which threads in and out of structure 4 through successive sets of structure spindle apertures 36 and corresponding valve spindle apertures 38. Cable stops 33 prevent spindle 26 from sliding through valve spindle apertures 38 and springs 22. Washers 35 could be disposed between cable stops 33 and springs 22, thus sandwiching each spring 22 between structure 4 and a cable stop 33.

In the preferred embodiment, spring assemblies 9 were spaced 12 inches apart. Valve 2 was made of aluminum, metal, synthetic, concrete, or other appropriate material, and skylight 12 was made of glass, plastic, or other appropriate transparent material. Spindles 26 were any appropriate elongate member, including but not limited to cable, chain, a metal or synthetic rod, bolt, etc. Springs 22 were commercially available compression springs. Cable stops 33 and washers 35 were commercially available components. Spindle stops 40 and spring stops 24 were metal, synthetic, or other appropriate material.

While a preferred embodiment of the invention has been illustrated herein, it is to be understood that changes and variations may be made by those skilled in the art without departing from the spirit of the appending claims.

DRAWING ITEM INDEX

-   2 valve -   3 valve seat -   4 structure -   6 door -   7 structure valve aperture -   8 window -   9 spring assembly -   10 broken window -   12 skylight -   14 storm wind -   15 spoiler -   16 arrow -   17 turbulent airflow -   18 escaping air -   20 arrow -   22 spring -   24 spring stop -   26 spindle -   28 arrow -   32 cable -   33 cable stop -   35 washer -   36 structure spindle aperture -   38 valve spindle aperture -   40 spindle stop -   42 arrow 

1. A pressure relief valve for structure comprising a valve sized to sit in a valve seat, said valve seat being disposed around a structure valve aperture, and means of resisting opening of said valve.
 2. The pressure relief valve for structure of claim 1 wherein said valve comprises a spoiler disposed around an edge of said valve, whereby lift caused by storm wind impinging on an upwind side of said valve is spoiled, thereby urging said upwind valve side to remain closed.
 3. The pressure relief valve for structure of claim 2 wherein said means of resisting opening of said valve comprises a plurality of spring assemblies disposed around said structure valve aperture, each said spring assembly comprising a spindle through a spring.
 4. The pressure relief valve for structure of claim 3 wherein each said spring assembly further comprises a spring stop at one end of said spindle, said spring being disposed between said spring stop and said structure, and an opposite one end of said spindle is attached to said valve.
 5. The pressure relief valve for structure of claim 3 wherein said valve comprises a plurality of valve spindle apertures, said structure comprises a structure spindle aperture corresponding to each said valve spindle aperture, each said spindle is slidably disposed within one said valve spindle aperture and a corresponding said structure spindle aperture, said spindle comprises a spring stop at one end and a spindle stop at an opposite end, and said valve is spring-loaded closed by means of said springs.
 6. The pressure relief valve for structure of claim 2 wherein said valve comprises a skylight.
 7. The pressure relief valve for structure of claim 2 wherein a shape of said valve is a spherical section.
 8. The pressure relief valve for structure of claim 2 wherein a shape of said valve is a spheroid section.
 9. The pressure relief valve for structure of claim 2 wherein said valve is spring-loaded closed sufficiently to open when subjected to a pressure differential of 1.5±1 psi.
 10. In combination a structure and a pressure relief valve for structure comprising a valve, a structure, and means of resisting opening of said valve, said structure comprising a structure valve aperture and a valve seat around said structure valve aperture, said valve being sized to seat in said valve seat.
 11. The pressure relief valve for structure of claim 10 wherein said valve comprises a spoiler disposed around an edge of said valve, whereby lift caused by storm wind impinging on an upwind side of said valve is spoiled, thereby urging said upwind valve side to remain closed.
 12. The pressure relief valve for structure of claim 11 wherein said valve is spring-loaded closed sufficiently to open when subjected to a pressure differential of 1.5±1 psi.
 13. The pressure relief valve for structure of claim 11 wherein said means of resisting opening of said valve comprises a plurality of spring assemblies disposed around said structure valve aperture, each said spring assembly comprising a spindle through a spring.
 14. The pressure relief valve for structure of claim 13 wherein each said spring assembly further comprises a spring stop at one end of said spindle, said spring being disposed between said spring stop and said structure, and an opposite one end of said spindle is attached to said valve.
 15. The pressure relief valve for structure of claim 13 wherein said valve comprises a plurality of valve spindle apertures, said structure comprises a structure spindle aperture corresponding to each said valve spindle aperture, each said spindle is slidably disposed within one said valve spindle aperture and a corresponding said structure spindle aperture, and said spindle comprises a spring stop at one end and a spindle stop at an opposite end.
 16. The pressure relief valve for structure of claim 11 wherein said valve comprises a skylight.
 17. The pressure relief valve for structure of claim 11 wherein a shape of said valve is a spherical section.
 18. The pressure relief valve for structure of claim 11 wherein a shape of said valve is a spheroid section.
 19. The pressure relief valve for structure of claim 11 wherein said means of resisting opening of said valve comprises a plurality of valve spindle apertures in said valve, a structure spindle aperture and a spring corresponding to each said valve spindle aperture, a cable passing through successive valve spindle apertures, structure spindle apertures and springs, and cable stops attached to said cable so as to compress at least one said spring when said valve opens.
 20. The pressure relief valve for structure of claim 11 wherein said valve is spring-loaded closed.
 21. The pressure relief valve for structure of claim 1 wherein a plan view shape of said valve and valve seat is circular.
 22. The pressure relief valve for structure of claim 10 wherein a plan view shape of said valve and valve seat is circular.
 23. The pressure relief valve for structure of claim 2 wherein a cross-sectional shape of said spoiler is circular.
 24. The pressure relief valve for structure of claim 11 wherein a cross-sectional shape of said spoiler is circular. 